Belgium's MyGov app does not work on GrapheneOS

Some background: MyGov.be is the official app covering all the federal public services in Belgium and allows access to official documents and works as an authenticator for official websites. In particular the authenticator function is important, as realistic alternatives are either using an e-ID identity card reader or Itsme, the latter being a collaboration between leading banks and telecom giants. Oddly enough, the Android app - developed by the federal government using taxpayer funds - is fully reliant on Google Play Services. More recently, it flat out refuses to load if you use GrapheneOS. The official reason for this is 'security'. I cannot help but find this laughable, for the very simple reason that the same app can be installed on a device running Android 10 without security updates. It is peculiar that the commercial alternative Itsme works perfectly fine on a device running GrapheneOS without Google Play Services. Either Itsme is taking an significant security risks, or the…